RSAP LO1

• centrifugal force

  inertia creates an outward seeking force to moving electrons, away from center of its orbit.
• Centripetal force

  due to the attractive pull between negatively and positively charged electrons, the electrons are attracted inward towards the nucleus.
• Electron binding energy

  The amount of energy required to remove an electron from the atom. Measured in electron volts (eV).
• The closer the distance to the nucleus an electron orbits, the more energy required to remove the electron.


  Ex. K shell has the highest electron binding energy
• Electron binding energy

  The higher the number of protons and electrons present, the higher the binding energy for the electron.
• Radiation speed

  Radiation that is emitted travels through space at the speed of light. (3x10^8 m/s)
• How radiation travels

  Radiation travels through space either as a particle or electromagnetic wave. It can move through matter/space and in a vacuum.
• Photon

  A photon is the smallest quantity of electromagnetic energy. It has no mass and no electrical charge. Measured in electron volts (eV).
• Sine wave

  Photons have continuously changing electrical and magnetic fields which causes them to move through space in an oscillating or sinusoidal pattern known as a sine wave.
• The electric field and the magnetic field are perpendicular to each other.

  
• The Electromagnetic Spectrum

  The amount of energy increases from left to right along the spectrum.

  
• A wave has four main properties: wavelength (λ), frequency (f), amplitude (v), and period.
• Frequency and wavelength are inversely proportional, so as one increases the other decreases.
• The velocity of an electromagnetic wave is the product of wavelength and frequency.


  v= λ f
• The higher the frequency of a wave, the higher the energy the photon has.
• The energy of an electromagnetic photon is calculated E= h f


  h is a constant called Planck's which equals 4.15x10^-15 eV
• Particle Theory

  Radiation can be classified by its effects when it interacts with matter, as either: ionizing or non-ionizing.
• Ionizing Radiation


  This means it has the ability to break atomic bonds that hold the molecules of matter together, producing positively and negatively charged particles.
• Ionizing radiation is classified into either Particulate or Electromagnetic.
• Ionization

  Addition or removal of an electron from an atom. Once ionized the atom becomes much more open to chemical activity. It can be harmful to the human body.
• Non-Ionizing Radiation

  The lower ultraviolet part of the electromagnetic spectrum, including visible light, infrared, microwaves, and radio waves.
• Ionizing Radiation- Particulate

  Alpha particles, Beta particles, Neutrons
• Ionizing Radiation- Electromagnetic

  Gamma rays and X-rays
• Particulate Radiation

  If a subatomic particle is ejected from an atom at a high speed, with sufficient kinetic energy, it is classified as particulate radiation, and is capable of causing ionization.
• Alpha Particles

  Consists of two protons and two neutrons. They have a large mass and can transfer large amounts of energy to other atoms orbital electrons, as a result lose energy quickly. Essentially harmless, due to low penetrability.
• Beta Particle

  Negative charge, lighter in weight than alpha particles- therefore penetrate farther into matter.
• Gamma Radiation

  Has no mass, no charge, and a short wavelength, high energy so they are capable of ionization.
• X-Ray

  X-rays are produced when fast moving electrons collide with atoms of metallic elements. Has a short wavelength and high penetrating power.
• Radiobiology

  The study of the action of ionizing radiation on living things.
• Who is responsible for X-rays?

  1. Referring physician 2. Radiographer 3. Radiologist
• ALARA

  As Low As Reasonably Achievable
• ORP

  Optimization for Radiation Protection
• What is the risk of X-rays?

  The main risk is the possibility of inducing a radiogenic cancer or genetic effect after irradiation.
• BERT

  Background Equivalent Radiation Time- compares the amount of radiation received during exam to natural radiation.
• Biological Effects of Radiation Exposure

  Effects happen because of damage to individual cells.
• Damage based on several different factors:

  Type of cells, Energy and type of radiation, Metabolic rate/ presence of oxygen, Amount of radiation, Age and sex, Area/amount of tissue exposed.
• Radiosensitivity: the relatively susceptibility of cells, tissues, organs, organisms, or other substances to damage from radiation.


  Law of Bergonie and Tribondeau
• Radiosensitivity of cells is directly proportional to their reproductive activity and inversely proportional to their degree of differentiation.
• How Ionizing radiation causes injury

  1. Linear Energy Transfer (LET), 2. Relative Biologic Effectiveness (RBE), 3. Oxygen Enhancement Ratio (OER).
• Linear Energy Transfer

  The average energy deposited per unit length along its pathway or track. The higher the LET, the greater the chance of producing significant biological damage.